“Something in the load of the vehicle shifted and it compromised the compressed natural gas fuel system, consequently there was a detonation of the fuel system that injured one of the people in the vehicle and there was also a fatality,” said Ed Janke, the director of Howard Public Safety.

The owners of Ace Manufacturing issued a statement.

"First and foremost, our thoughts and prayers go out to the family of the truck driver who lost his life in this accident, as well as another worker who was injured,” wrote Kelley Krouth and Brian Lakari, the co-owners of the company. “For privacy reasons, we are not releasing the names of those involved. We are a small and close-knit company and this has shaken and saddened all of us.”

For a while, authorities were worried about the potential of more explosions. Area businesses were evacuated but they were able to return.

“We notified Green Bay Hazmat team to assist us in our investigation,” said Janke. “They found that the vehicle had actually off gassed and we determined the scene was safe.”

Those near the explosion say it's something they won't soon forget.

“It wasn't thunder,” said Kevin Lindner of Howard. “That's your first intuition, but like I said it didn't sound like thunder so first thing that goes through your mind is explosion and that's what it was.”

Ace Manufacturing canceled its second shift operation Thursday, but planned to resume work with its third shift.